Introduction

Background

SNOMED CT terminology provides a common language that enables a consistent way of indexing, storing, retrieving, and aggregating clinical data across specialties and sites of care.

SNOMED International maintains the SNOMED CT technical design, the content architecture, the SNOMED CT content (includes the concepts table, the descriptions table, the relationships table, a history table, and ICD mappings), and related technical documentation.

Purpose

This document provides a summarized description of the content changes included in the August 2025 release of SNOMED Clinical Terms^® (SCT) International Edition.

It also includes notes detailing the known content or technical issues where the root cause is understood, the fix has been discussed and agreed to, but has yet to be implemented.

The SNOMED International release notes are available alongside the August 2025 International Edition.

Scope

This document is written for the purpose described above and is not intended to provide details of the technical specifications for SNOMED CT or encompass every change made.

Audience

The audience includes National Release Centers, WHO-FIC release centers, vendors of electronic health records, terminology developers and managers who wish to have an understanding of changes that have been incorporated into the August 2025 International Edition.

Please note, you may have to register for a Confluence user account in order to access the links included in these release notes.

Content Development Activity

Summary

Continuous quality improvement and enhancement of existing content is an ongoing process undertaken by SNOMED International in preparation for every release. The August 2025 International Edition has seen a continuation of the work driven by contributions from: Kaiser Permanente i.e. Convergent Medical Terminology (CMT), Global Medical Device Nomenclature Agency (GMDNA), Orphanet and other domain specific collaborations as well as requests received via the Content Request System (CRS). 

Information about editorial decisions may be found in the SNOMED CT Editorial Guide; mapping guidance for ICD-10 can be found here.

Quality Initiative

The Quality Initiative (QI) project is the implementation of the Quality Strategy. After a successful pilot project for the July 2018 Edition release, the next stage has been implemented for subsequent releases including August 2025. 

Quality improvement tasks are being deployed to improve internal structural consistency and ensure compliance with editorial policy related to the stated modeling of content. Additionally, correction or addition of defining relationships is being carried out to accurately reflect current clinical knowledge and ensure the semantic reliability of descriptions associated with a concept.

Update Hierarchy 424128006|Decompression (procedure)|

As part of the ongoing Quality Improvement (QI) work for decompression procedures, updates have been made to address inconsistencies in the modeling of spinal decompression procedures. This includes refinements to align with established editorial guidelines and ensure consistent representation.

In addition, a number of concepts referring to “primary” procedures have been inactivated. This action is consistent with SNOMED editorial guidance, which discourages the use of “primary” and “secondary” qualifiers in procedure terminology due to ambiguity and inconsistent clinical usage, for further information please see Primary vs secondary procedures.

Number of concepts edited (approx): 53

Inactivation of 363743006 |Navigational concept (navigational concept)

The entire navigational hierarchy << 363743006 |Navigational concept (navigational concept)| has been inactivated in bulk with reason 'Non-conformance to Editorial Policy' and with no historical associations specified.

Navigational concepts were created to group other concepts without explicit regard for defining attributes(since there were none). Their purpose was to provide top level groupers for subsets and reference sets used in implementations. Because the Reference Set mechanism is now available, there is no longer a need for navigational concepts in the International Release; however, they can be added at the national or lower level.  Further information is available in this briefing note.

Body Structure 

Update Congenital Disorders Modeled with Fetal Body Structures

The concept model for approximately 60 fetal procedures and findings has been updated. The updated model employs the attribute 246454002 |Occurrence (attribute)| with the value 303112003 |Fetal period (qualifier value)| and its subconcepts for modeling purposes. Finding and procedure sites have been revised to include canonical or morphological structures (excluding unique fetal structures) such as persistent or malformed structures.

For example, concepts modeled with site 'fetal head structure' have been remodeled using 'head structure' in combination with 'fetal period' occurrence.

In addition, concepts relating to conjoined twins have also been updated with canonical structures. These concepts have been remodeled by either canonical structures, e.g. cranial vault, persistent structures e.g. persistant , or developmental structures that exist in fetal and early development stages e.g. premaxilla.

The related fetal body structures have been reviewed and their relationships removed if they are not unique to the fetus.

Number of concepts edited (approx): 100

Update Peripheral and Systemic Blood Vessel Concepts

The FSN for 281157001 |Systemic vascular structure (body structure)| has been updated to "Systemic blood vessel structure" with the additional parent 51840005 |Systemic circulatory system structure (body structure)|.

The FSN for 51833009 |Peripheral vascular system structure (body structure)| has been updated to "Peripheral blood vessel structure".

The direct subconcepts of "Systemic blood vessel structure" and "Peripheral blood vessel structure" have been reviewed and updated.

The descendants of 113257007 |Structure of cardiovascular system (body structure)| has been reorganized into 118970008 |Structure of cardiovascular system subdivision (body structure)|.

Number of concepts edited (approx): 40

SEP and Laterality Anatomy Reference Sets

The release file for the lateralizable body structure reference set has been updated and validated.

The release file for the SEP reference set has been updated and validated.

Clinical Finding

Alignment of FSN for Mouth Region Disorders

A mismatch between FSN and modeling for two concepts has been identified:

• 1217617009 |Kaposi sarcoma of internal part of mouth (disorder)|
• 372001002 |Primary malignant neoplasm of oral cavity (disorder)|

Both concepts have been modeled using700016008 |Structure of region of internal part of mouth (body structure)|.

To ensure consistency with editorial guidance:

• FSNs were updated to refer to 'internal part of mouth' to match the modeled site
• Existing terms referencing 'oral cavity' have been retained as preferred terms to aid searchability

This change was part of a review that identified 35 similar concepts. All have now been updated to maintain consistency between FSNs and anatomical modeling.

Number of concepts edited (approx): 36

Inactivation of 364935004|Finding related to ability to transfer between wheelchair and toilet (finding)| and Descendants

364935004 |Finding related to ability to transfer between wheelchair and toilet (finding)| and descendants and 302274006 |Ability to transfer between wheelchair and toilet (observable entity)| have been inactivated with reason ambiguous. Concepts for the specific direction of transfer are available, e.g., 715087003 |Able to transfer from wheelchair to toilet (finding)|, 715083004 |Able to transfer from toilet to wheelchair (finding)|.

Number of concepts edited (approx): 7

Secondary Disorders

Work is in progress to address the modeling of secondary disorders for this Content Tracker. 

General concept inclusion (GCI) axioms have been implemented to ensure the automatic classification of secondary disorders. Changes have been made in the following content areas:

• 8801005 |Secondary diabetes mellitus (disorder)| - 29 concepts remodeled
• 1162307001 |Secondary osteolysis (disorder)| - 8 concepts remodeled
• 60738003 |Secondary myopathy (disorder)| - 2 concepts remodeled

Number of concepts edited (approx): 40

Procedure

Reduction of dislocation

A review and remodeling of the concepts related to Reduction of dislocation of joint of shoulder region and Reduction of dislocation of shoulder region has been undertake as part of the work for this content tracker. The changes align with the anatomical model for joints of limbs where 'Joint of shoulder' is a synonym for 85537004 |Glenohumeral joint structure (body structure)| and a subtype of 31398001 |Joint structure of shoulder region (body structure)|.

Procedure concepts for 'reduction of dislocation' stating "Shoulder", "Joint of shoulder", "Shoulder joint", have been  modeled with 405813007 |Procedure site - Direct (attribute)| = 85537004 |Glenohumeral joint structure (body structure)|. A synonym stating the "Glenohumeral joint" has added for reference. e.g "Reduction of dislocation of shoulder" now has the synonym "Reduction of dislocation of glenohumeral joint".

Number of concepts edited (approx): 40

Radiographic Imaging

Work is progressing for this content tracker for information please see the informational briefing note here. 

For the August 2025 release a review of 315292000|Contrast swallow (procedure) and descendants has been undertaken. Subtypes that do not specify an imaging modality/align with the editorial guidance have been reviewed for inactivation and replaced by an imaging specific procedure concept.

Pharmaceutical/Biologic Product

Inactivation of Fluoride Medicinal Products

As part of ongoing content quality improvement, 9 concepts related to fluoride in the medicinal products hierarchy, including 3 clinical drugs, have been inactivated. The following concepts have been inactivated:

• 374017007 |Product containing precisely fluoride 1.1 milligram/1 each conventional release oral tablet (clinical drug)|
• 374018002 |Product containing precisely fluoride 2.2 milligram/1 each conventional release oral tablet (clinical drug)|
• 374019005 |Product containing precisely fluoride 550 microgram/1 each conventional release oral tablet(clinical drug)|
• 350594000 |Product containing fluoride (medicinal product)|
• 775997006 |Product containing only fluoride (medicinal product)|
• 437878007 |Product containing fluoride in oral dose form (medicinal product form)|
• 1141896001 |Product containing fluoride in oromucosal dose form (medicinal product form)|
• 779288009 |Product containing only fluoride in oral dose form (medicinal product form)|
• 779289001 |Product containing only fluoride in oromucosal dose form (medicinal product form)|

3 new clinical drugs have been created as target replacements:

• 1370823002 |Product containing precisely sodium fluoride 550 microgram/1 each conventional release chewable tablet (clinical drug)|
• 1370821000 |Product containing precisely sodium fluoride 1.1 milligram/1 each conventional release chewable tablet (clinical drug)|
• 1370824008 |Product containing precisely sodium fluoride 2.2 milligram/1 each conventional release chewable tablet (clinical drug)|

Collaboration/Harmonization Agreements

Convergent Medical Terminology (CMT)

243 new concepts have been added for the August 2025 release. Key topic areas were open wounds due to bites, endometriosis, chemical burns, device disorders and musculoskeletal disorders.

Orphanet

Working in collaboration with Orphanet efforts are ongoing to update rare disease concepts in SNOMED CT to maintain alignment with Orphanet for the annual update of the SNOMED CT to Orphanet Maps. In scope content has been annotated with attribution to Inserm Orphanet.

All of the concepts added for the Orphanet project have been mapped to ICD-10.

Cancer Synoptic Reporting

Cancer synoptic reports are used by many member countries to record pathology examination of cancer specimens including the College of American Pathologists (US and Canada), Royal College of Pathology (UK), Royal College of Pathology Australasia (Australia, New Zealand), PALGA (The Netherlands), Swedish Society of Pathology, and others.

For more information about this project, please see Cancer Synoptic Reporting Clinical Project Group 

International League Against Epilepsy (ILAE)

In line with approved harmonized terminology, this project is working on alignment including restructuring to update the hierarchy  << 313307000 |Epileptic seizure (finding)|.

Further information about this collaboration is available here.

Gravity

Seven new concepts have been added with the two key content areas being family strengthening procedures and incarceration findings.

Internal Quality Improvement

Machine Readable Concept Model (MRCM) Changes

There have been no changes for MRCM in the August 2025 International Edition.

Future changes that are currently in progress can be viewed via the MRCM Daily Build Browser

Please see Early Visibility Release Notifications for future planned changes to MRCM.

Annotation Reference Set

The addition of content for the Annotations refset was commenced in the July 2024 International Edition release and is ongoing for attribution of in scope content that is part of a collaboration agreement. Where content with attribution no longer falls into scope for a collaboration agreement, the attribution has been inactivated.

SNOMED CT derived products

SNOMED CT - ICD-10 map

The SNOMED CT to the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (© World Health Organization 1994) 2016 Version map (SNOMED CT to ICD-10 Map) is included in the SNOMED CT International Edition as a Baseline. The SNOMED CT to ICD-10 Map was created to support the epidemiological, statistical and administrative reporting needs of SNOMED International member countries and WHO Collaborating Centers.

The SNOMED CT to ICD-10 Map is released in Release Format 2 (RF2) only. It is located in the file der2_iisssccRefset_ExtendedMapFull_INT_20200731.txt, which is in the Map folder under Refset, in each of the three RF2 Release Type folders. 

The SNOMED CT to ICD-10 Map is released as Refset 447562003 |SNOMED CT to ICD-10 extended map (foundation metadata concept).

The ICD-10 Mapping Technical Guide (including exemplars) is hosted here https://confluence.ihtsdotools.org/display/DOCICD10.

Content Development Activity Summary

The map is a directed set of relationships from SNOMED CT source concepts to ICD-10 target classification codes.  The SNOMED CT source domains for the map are constrained to subtypes of 404684003 |Clinical finding (finding)|, 272379006 |Event (event)|, and 243796009 |Situation with explicit context (situation)|. The target classification used is the ICD-10 WHO version 2016 (https://icd.who.int/browse10/2016/en#/).

Mapped content for August 2025 release

The map provided for this release has been updated and represents a complete map from the August  2025 release of the SNOMED CT International Edition to the ICD-10 WHO version 2016.

This includes:

• Addition of 659 new mapped concepts

• Reactivation of 1 previously published maps
• Updates to 243 existing mapped concepts
• Retirement of 329 mapped concepts

The SNOMED CT to ICD-O morphology map has zero (0) additions for this release.

We welcome feedback on any issues that users may detect when deploying the map. Issues can be reported to mapping@snomed.org.

SNOMED CT to OWL conversion and classification

The repository containing the toolkit enabling simple SNOMED CT to OWL conversion and classification can be found here, including documentation on its use: https://github.com/IHTSDO/snomed-owl-toolkit

Please contact SNOMED International at support@snomed.org if you would like to provide any feedback on ways to extend and improve the new toolkit.

Technical notes

Known Issues

Known Issues are content or technical issues where the root cause is understood, and the resolution has been discussed and agreed but has yet to be implemented.  This can be due to a number of reasons, from lack of time within the new monthly editing cycles, to the risk of impact to the stability of SNOMED CT if the fix were to be deployed at that stage in the Product lifecycle.  

For the current SNOMED CT International Edition, the following Known Issues were identified, and agreed to be resolved in future editing cycles:

Resolved Issues

Resolved issues are Known Issues which were not fixed as part of the previous release lifecycle, but which have now been resolved in the latest release.  They can also be issues found during testing of the current release, which were resolved before the final deployment of the Production release.  Finally they can be issues which were reported or found during the testing phase, but which have been closed without any action taken.  

The Resolved Issues for the current SNOMED CT International Edition can be found here:

Technical updates

RF2 package format

The RF2 package convention dictates that all relevant files are included, regardless of whether or not there is content to be included in each release.  Therefore, the package contains a mixture of files which contain both header rows and content data, and files that (intentionally) include only header records.  The reason that these "empty" files are included in the package is to draw a clear distinction between:

1. ...files that have been deprecated (and therefore removed from the package completely), due to the content no longer being relevant to RF2 in future releases 

2. ...files that happen to contain no data in this particular release (and are therefore included in the package with just a header record), but are still relevant to RF2, and could therefore contain content in future releases.

This allows users to easily distinguish between the two scenarios, as otherwise if files in option 2 were left out of the package it could be interpreted as an error, rather than an intentional lack of content in that release.

 Proposal to increase the maximum length of Description Types

Please find below the link to the recent announcement on the proposal to increase the limit of characters allowed in Descriptions:

• https://confluence.ihtsdotools.org/pages/viewpage.action?pageId=238158325

A community consultation was launched to solicit feedback on a proposal to increase the size limits of SNOMED CT concept descriptions to 4096 from the current limit of 255 characters. While this change does not represent a modification of the existing specification, it could be disruptive to implementers who have coded fixed length limits into their systems.  

Please read the full proposal, along with the latest Q&A blog post which details the proposed change, its potential benefits, the feedback process and timelines, and the issues that may need to be considered in such an update:

• https://confluence.ihtsdotools.org/mag/community-consultations/snomed-international-proposal-to-increase-description-length-limit
• https://www.snomed.org/news/blog%3A-snomed-international-seeks-community-feedback-on-proposed-description-character-limit-increase

As always, SNOMED International greatly appreciated all feedback provided before the deadline (which was Dec 31, 2024).  A summary of the feedback will be collated and disseminated in 2025, alongside a plan for the transition.

Early visibility of impending changes in the upcoming 2025 Monthly International Edition releases

Please see the Early Visibility Release Notifications Confluence page for details of forthcoming changes.